#!/usr/bin/env bash

# A/B the PreToolUse(Read) REDIRECT hook (P1): does steering Read → codegraph_node

# file-view actually move the agent off Read during implementation? BOTH arms use

# the CURRENT build with codegraph attached and pre-warmed; the only difference is

# the hook. Isolates the hook's behavioral effect from the build/file-view change

# (use ab-new-vs-baseline.sh for the build A/B).

#

# arm [nohook] — codegraph on, no hook (does the better file-view get picked on its own?)

# arm [hook] — codegraph on, + redirect hook (does routing close it?)

#

# Reliable attach (works nested): each arm pre-warms a persistent daemon and skips

# the startup re-exec (CODEGRAPH_WASM_RELAUNCHED=1), so claude connects before the

# agent's first turn. Judge by ACTUAL codegraph usage in parse-run.mjs's "by type",

# not claude's init snapshot (which can read pending even when it then connects).

#

# Usage: ab-hook.sh <indexed-repo> "<implementation task>" [runs-per-arm]

# <indexed-repo> a repo with a .codegraph index (copied per arm; never mutated)

# "<task>" a GENUINELY-NEW implementation task (verify it isn't already done)

# [runs-per-arm] default 2 (n=1 is noisy — the doctrine says >=2)

# Env: AGENT_EVAL_OUT (default: /tmp/ab-hook)

set -uo pipefail

TARGET="${1:?usage: ab-hook.sh <indexed-repo> \"<task>\" [runs-per-arm]}"

TASK="${2:?task required}"

RUNS="${3:-2}"

ENGINE="$(cd "$(dirname "$0")/../.." && pwd)"

BIN="$ENGINE/dist/bin/codegraph.js"

HOOK="$ENGINE/scripts/agent-eval/redirect-read-hook.sh"

OUT="${AGENT_EVAL_OUT:-/tmp/ab-hook}"

PARSE="$ENGINE/scripts/agent-eval/parse-run.mjs"

command -v claude >/dev/null || { echo "claude CLI not on PATH"; exit 1; }

command -v jq >/dev/null || { echo "jq not on PATH (the hook needs it)"; exit 1; }

[ -d "$TARGET/.codegraph" ] || { echo "target not indexed: run 'codegraph init $TARGET' first"; exit 1; }

chmod +x "$HOOK"

cleanup() { pkill -9 -f "serve --mcp --path $OUT/" 2>/dev/null; }

trap cleanup EXIT

mkdir -p "$OUT"

echo "###### engine=$ENGINE"

echo "###### target=$TARGET runs/arm=$RUNS"

echo "###### task=$TASK"

echo

( cd "$ENGINE" && npm run build >/dev/null 2>&1 ) && echo "built"

# A settings file carrying ONLY the PreToolUse(Read) redirect hook.

HOOK_SETTINGS="$OUT/hook-settings.json"

jq -n --arg cmd "bash $HOOK" \

'{hooks:{PreToolUse:[{matcher:"Read",hooks:[{type:"command",command:$cmd}]}]}}' > "$HOOK_SETTINGS"

prewarm() { # target — spawn a persistent daemon and wait for its socket

pkill -9 -f "serve --mcp --path $1" 2>/dev/null

CODEGRAPH_DAEMON_IDLE_TIMEOUT_MS=1800000 node "$BIN" serve --mcp --path "$1" </dev/null >/dev/null 2>&1 &

node -e 'const fs=require("fs");let n=0;const t=setInterval(()=>{if(fs.existsSync(process.argv[1]+"/.codegraph/daemon.sock")){clearInterval(t);process.exit(0)}if(n++>150){clearInterval(t);process.exit(1)}},100)' "$1" \

&& echo " daemon warm: $1" || echo " WARN: daemon never bound for $1"

}

run_one() { # arm-label, run-index, use-hook(0|1)

local label="$1" idx="$2" hook="$3"

local tgt="$OUT/t-$label-$idx" c="$OUT/mcp-$label.json"

rm -rf "$tgt"

rsync -a --exclude node_modules --exclude .git --exclude dist --exclude .codegraph "$TARGET/" "$tgt/"

node "$BIN" init "$tgt" >/dev/null 2>&1

printf '{"mcpServers":{"codegraph":{"command":"env","args":["CODEGRAPH_WASM_RELAUNCHED=1","node","%s","serve","--mcp","--path","%s"]}}}' "$BIN" "$tgt" > "$c"

prewarm "$tgt"

local extra=()

[ "$hook" = "1" ] && extra=(--settings "$HOOK_SETTINGS")

echo "----- [$label] run $idx -----"

# ${extra[@]+...} guard: bash 3.2 (macOS) under `set -u` errors on an empty

# array expansion otherwise, which would skip the no-hook arm's claude run.

( cd "$tgt" && claude -p "$TASK" \

--output-format stream-json --verbose --permission-mode bypassPermissions \

--model opus --max-budget-usd 4 --strict-mcp-config --mcp-config "$c" ${extra[@]+"${extra[@]}"} \

</dev/null > "$OUT/run-$label-$idx.jsonl" 2>"$OUT/run-$label-$idx.err" )

node "$PARSE" "$OUT/run-$label-$idx.jsonl" 2>&1 | grep -E "by type|Result" || echo " (parse failed — see $OUT/run-$label-$idx.jsonl)"

pkill -9 -f "serve --mcp --path $tgt" 2>/dev/null

echo

}

for i in $(seq 1 "$RUNS"); do run_one nohook "$i" 0; done

for i in $(seq 1 "$RUNS"); do run_one hook "$i" 1; done

echo "###### DONE. Compare [nohook] vs [hook] 'by type' — Read should fall and"

echo "###### mcp__codegraph__codegraph_node should rise in the [hook] arm. Logs: $OUT"